Improvement in door-bells



0. W. STOW.

l noon-HELM.

l No.181,604, Patented Aug. 29, v187B.

NITED i'rATES PATENT IMPROVEMENT IN Doon-BELLS.

Specication forming part of Letters Patent No. 181,604, dated August 29,1876; application tiled June 2, 1876.

of which the following is a specification:

AThe invention relates to the peculiar construction of the parts withreference to securing them to the door, and compensating for the variousthicknesses of doors, all as hereinafter described.

In the accompanying drawing, Figure l is a lfront elevation of thestriking mechanism of a door-bell which embodies my invention 5 and Fig.2 is a vertical section on a line passing through its center of adoor-bell which embodies my invention.

A designates a central and rotating cani, held in place, as hereinafterdescribed, within a central chamber. The stud B, which supports the bellC, is secured to and projects from the base-plate D. An oscillatinghammer, E, is hun'g to said plate D, said hammer carrying an arm, a,which engages with the central cam A, so as to be tripped thereby, andit is held in contact with said cam by means of the spring b, constantlypressing upon the arm a ofthe hammer E. By rotating the cam in suchdirection that its top travels away from the arm c, said arm will bethrown outward as it rides up the incline of the cam, and its oppositeend inward, as indicated by broken lines in Fig. l. So soon as theradial shoulder ofthe cam passes the hammer-arm a, the spring b forcesthe arm a suddenly inward, and the hammer proper outward, to strike thebell C in a well-known manner. I secure the central vcam A tirmly to itsshaft F; and to the opposite end, by means of a nut or other convenientfastening, I secure a crank, G, or other handle, by means of which theshaft may be rotated. Upon each side ofthe door H I secure a. circularplate, c c', the latter being secured to the outside by means of screws,and may be as ornamental as desired, and also its contour may be ofother form than circular. Upon each of these plates I form hollow bossesd d, and the cam-shaft F is fitted to turn in these bosses, as showinThe exterior of these bosses should be of a size to tools.

In order to secure the device upon a door, a hole corresponding in sizeto the. bosses is bored straight through the door. The crank orhandle isremoved from the cam-shaft, and the plates c c are placed upon the door,with their bosses resting in the hole so made in the door to receivethem, and the outer plate c' may be secured by screws when the crank canvbe replaced on the cam-shaft. In the back side of the base-plate D Iform a circular recess, of a size anddepth to correspond with the sizeand thickness of the circular plate c, and which recess in the drawingis filled by said plate. In front of the plate c and its recess achamber is formed in the plate D, of a diameter large enough to allowthe central cam free play, and of a depth fully equal to the thicknessofthe cam, for a purpose herei after specified. At one side of thischamber the walls are cut away, as shown, in order to allow thehammer-arm a and cam A to come in con tact with each other. In order tosecure the boss-plate D upon the door, its proper position is rstdetermined by placing it over the plate c, and letting said plate intoits recess in the plate D, when said plate may be secured in place byscrews. The central cam is then prevented from working toward the bellby the front wall of the cam-chamber, which chamber should be shallowenough to hold the cam within the door anddeep enough not to bind thecam and cause it to turn hard. The cam, by striking the plate c, will beprevented from Working in the opposite direction-that is, the end chaseof the cam and its shaft is regulated by the plate c and front wall ofthe cam chamber. The cam shaft should be made long enough for thethickest door, and by the above construction Will readily accommodateitself to varying thicknesses of doors, the only variance heilig that ina thin door the crank end will project a little farther' than it does ina thick door. The device is also very cheaply made, and can be much moreconveniently attached than can ordinary crank-bells.

I claim as my inventionl. The plate D, having the central can1- FFIE.

chamber in the back to receive the cam a, subi 3. The plate D, carryingthe stud. B, and stantially as described, and for the purpose having theWalls of the central chamber upon speced. one side cut*J away,substantially as described,

2. The cam A, having the bearings for its and for the purpose specified.shaft secured to the door, and detached from v ORSON W. STOW. the platewhich carries the hammer, substan- Witnesses: tially as described, andfor the purpose speci- RALPH I. CRISSEY,

fled. H. J. HOLT.

